1. Field of the Invention
This invention relates generally to apparatus for drilling oil wells, and more particularly to an improved drilling sub of the type constructed to be used in connection with a drill bit for creating a vortex in a borehole adjacent the drill bit.
2. Description of the Prior Art
The present invention is an improved version of the structure disclosed in U.S. patent application Ser. No. 169,676 of Hayatdavoudi et al., filed July 17, 1980 for DOWNHOLE VORTEX GENERATOR and assigned to the assignee of the present invention.
The structure disclosed in the Hayatdavoudi et al. application includes a drilling sub having a cylindrical housing with an upper end adapted to be connected to a drill string and a lower end adapted to be connected to a drill bit. An open cavity is disposed in the outer cylindrical surface of the housing. A longitudinal passageway is disposed through the housing. A transverse passageway means is disposed in the housing with a first end communicated with the longitudinal passageway and a second end communicated with the open cavity, for taking a portion of drilling fluid from the longitudinal passageway and for ejecting said portion of drilling fluid from the second end of the transverse passageway means with a non-radial velocity component in a plane normal to a longitudinal axis of the housing.
One difficulty encountered with the apparatus of the Hayatdavoudi et al. application is the complexity of construction of the transverse passageway means.